Synthesis and Properties of [3]Rotaxanes with Two Oligo(para-phenylene) Axles.

Oligo(para-phenylene) (PPn) is a π-conjugated compound where phenylene units are directly connected at the 1,4-positions. Utilizing the catalytic activity of the macrocyclic dihydrodibenzophenanthroline-Ni complex, we succeeded in the synthesis of [3]- and [2]rotaxanes with PPn axles by biaryl coupling. The size of the macrocycle was critical to synthesize [3]rotaxanes, which consist of two oligo(para-phenylene) axles, in good yields.

Regio- and Enantioconvergent Hydroallylation of Acrylates Enabled by γ-Silyl-Substituted Allyl Acetates.

Transition-metal-catalyzed asymmetric allylic substitution provides an efficient route to chiral organic molecules featuring an allyl moiety, key intermediates in the synthesis of biologically active compounds. However, the use of unsymmetrical 1,3-disubstituted allyl electrophiles has been severely constrained by the challenges of achieving both regio- and stereoselectivity simultaneously. Herein, we present γ-silyl-substituted allyl acetates as highly effective electrophiles for a regio- and enantioconvergent hydroallylation, enabling the construction of vicinal stereogenic centers.